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/*
* Copyright (C) 2012 Martin Storsjo
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "attributes.h"
#include "hmac.h"
#include "md5.h"
#include "sha.h"
#include "mem.h"
#define MAX_HASHLEN 20
#define MAX_BLOCKLEN 64
struct AVHMAC {
void *hash;
int blocklen, hashlen;
void (*final)(void*, uint8_t*);
void (*update)(void*, const uint8_t*, int len);
void (*init)(void*);
uint8_t key[MAX_BLOCKLEN];
int keylen;
};
static av_cold void sha1_init(void *ctx)
{
av_sha_init(ctx, 160);
}
AVHMAC *av_hmac_alloc(enum AVHMACType type)
{
AVHMAC *c = av_mallocz(sizeof(*c));
if (!c)
return NULL;
switch (type) {
case AV_HMAC_MD5:
c->blocklen = 64;
c->hashlen = 16;
c->init = av_md5_init;
c->update = av_md5_update;
c->final = av_md5_final;
c->hash = av_md5_alloc();
break;
case AV_HMAC_SHA1:
c->blocklen = 64;
c->hashlen = 20;
c->init = sha1_init;
c->update = av_sha_update;
c->final = av_sha_final;
c->hash = av_sha_alloc();
break;
default:
av_free(c);
return NULL;
}
if (!c->hash) {
av_free(c);
return NULL;
}
return c;
}
void av_hmac_free(AVHMAC *c)
{
if (!c)
return;
av_free(c->hash);
av_free(c);
}
void av_hmac_init(AVHMAC *c, const uint8_t *key, unsigned int keylen)
{
int i;
uint8_t block[MAX_BLOCKLEN];
if (keylen > c->blocklen) {
c->init(c->hash);
c->update(c->hash, key, keylen);
c->final(c->hash, c->key);
c->keylen = c->hashlen;
} else {
memcpy(c->key, key, keylen);
c->keylen = keylen;
}
c->init(c->hash);
for (i = 0; i < c->keylen; i++)
block[i] = c->key[i] ^ 0x36;
for (i = c->keylen; i < c->blocklen; i++)
block[i] = 0x36;
c->update(c->hash, block, c->blocklen);
}
void av_hmac_update(AVHMAC *c, const uint8_t *data, unsigned int len)
{
c->update(c->hash, data, len);
}
int av_hmac_final(AVHMAC *c, uint8_t *out, unsigned int outlen)
{
uint8_t block[MAX_BLOCKLEN];
int i;
if (outlen < c->hashlen)
return AVERROR(EINVAL);
c->final(c->hash, out);
c->init(c->hash);
for (i = 0; i < c->keylen; i++)
block[i] = c->key[i] ^ 0x5C;
for (i = c->keylen; i < c->blocklen; i++)
block[i] = 0x5C;
c->update(c->hash, block, c->blocklen);
c->update(c->hash, out, c->hashlen);
c->final(c->hash, out);
return c->hashlen;
}
int av_hmac_calc(AVHMAC *c, const uint8_t *data, unsigned int len,
const uint8_t *key, unsigned int keylen,
uint8_t *out, unsigned int outlen)
{
av_hmac_init(c, key, keylen);
av_hmac_update(c, data, len);
return av_hmac_final(c, out, outlen);
}
#ifdef TEST
#include <stdio.h>
static void test(AVHMAC *hmac, const uint8_t *key, int keylen,
const uint8_t *data, int datalen)
{
uint8_t buf[MAX_HASHLEN];
int out, i;
// Some of the test vectors are strings, where sizeof() includes the
// trailing null byte - remove that.
if (!key[keylen - 1])
keylen--;
if (!data[datalen - 1])
datalen--;
out = av_hmac_calc(hmac, data, datalen, key, keylen, buf, sizeof(buf));
for (i = 0; i < out; i++)
printf("%02x", buf[i]);
printf("\n");
}
int main(void)
{
uint8_t key1[16], key3[16], data3[50], key4[63], key5[64], key6[65];
const uint8_t key2[] = "Jefe";
const uint8_t data1[] = "Hi There";
const uint8_t data2[] = "what do ya want for nothing?";
AVHMAC *hmac = av_hmac_alloc(AV_HMAC_MD5);
if (!hmac)
return 1;
memset(key1, 0x0b, sizeof(key1));
memset(key3, 0xaa, sizeof(key3));
memset(key4, 0x44, sizeof(key4));
memset(key5, 0x55, sizeof(key5));
memset(key6, 0x66, sizeof(key6));
memset(data3, 0xdd, sizeof(data3));
// RFC 2104 test vectors
test(hmac, key1, sizeof(key1), data1, sizeof(data1));
test(hmac, key2, sizeof(key2), data2, sizeof(data2));
test(hmac, key3, sizeof(key3), data3, sizeof(data3));
// Additional tests, to test cases where the key is too long
test(hmac, key4, sizeof(key4), data1, sizeof(data1));
test(hmac, key5, sizeof(key5), data2, sizeof(data2));
test(hmac, key6, sizeof(key6), data3, sizeof(data3));
av_hmac_free(hmac);
return 0;
}
#endif /* TEST */
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